Many surgical instruments used in modern medical procedures generate smoke plumes as a by-product. Examples of such surgical instruments are lasers, electrosurgical units, laproscopes, drills and ultrasonic devices. Additionally, chemical mixes used in medical procedures can generate hazardous vapors also categorized as smoke plumes.
Many times the smoke plume from a medical procedure has a distinct and unpleasant odor. Accordingly, it is desirable to remove the smoke plume for the convenience of the staff.
However, health concerns raise a more significant reason to remove smoke plumes. It is known that smoke plumes can carry active particles such as viruses, bacteria mycobacteria and other microbes. These particles may be transmitted to the staff performing the medical procedure through contact with the plume. Furthermore, these particles can remain suspended in the operating room thus exposing the next patient or surgical staff. Examples of active particles known to exist in some smoke plumes are mycobacterium tuberculosis, condylomata acuminata, human immunodeficiency virus DNA, and human papilloma virus DNA.
Recently, government agencies have begun to investigate smoke plumes and advise the removal or filtering of smoke plumes generated by laser surgery. See "OSHA Technical Manual--Section V--Chapter 1 Appendix V:1-3, Physical Agents", "OSHA Technical Manual--Section V--Chapter 1, Hospital Investigations: Health Hazards" and "Health Hazard Information Bulletin: Hazards of Laser Surgery Smoke", Apr. 11, 1988. This concern has extended to other procedures generating smoke plumes such as electrosurgery. See "Standard Interpretations and Compliance Letters--Hazards of Smoke Generated from Surgical Procedures" at http://www.osha-slc.gov. Furthermore, the "1996 Standard & Recommended Practices" issued by the Association of Operation Room Nurses, Inc. recommends removal of smoke plumes during electrosurgical procedures, and the Center for Disease Control and Prevention (CDC) and the National Institute for Occupational Safety and Health (NIOSH) issued in Sep. of 1996 issued a Hazard Control II (HCII) entitled "Control of Smoke from Laser/Electric Surgical Procedures" similarly recommending removal of smoke plumes generated by electrosurgery.
Three methods are known to control smoke plumes: centralized vacuum/local filter, local vacuum/local filter and centralized vacuum/centralized filter unit.
Centralized vacuum systems have been used in health care facilities for decades. A central vacuum is connected to a duct system extending throughout the facility. The duct system terminates at a number of wall outlets in a plurality of procedure rooms. These units are designed to remove fluids and small particles generated by medical procedures (e.g., blood and bone chips).
The first response by the industry to address the identified hazards of smoke plumes was to adapt the known centralized vacuum systems into centralized vacuum/local filter systems capable of filtering smoke plumes. A centralized vacuum/local filter system generally comprises the existing centralized vacuum system, two lengths of flexible tubing and a local filter. One end of the first length of flexible tubing is connected to the centralized vacuum system wall outlet. The other end of the first section of tubing is connected to the exhaust of a local filter. One end of the second section of flexible tubing is connected to the inlet end of the local filter, and the other end of the second section of flexible tubing is then positioned adjacent the location of the smoke plume. The suction created by the central vacuum draws the smoke plume sequentially through the first flexible tubing section, the local filter, the second flexible tubing section and the duct work of the centralized vacuum system.
Centralized vacuum/local filter systems have deficiencies. The vacuum power generated is limited by the preexisting central vacuum. Some filters are difficult to use as central vacuums were not developed to create a pressure drop across robust filters. Accordingly, the efficiency of the filtration is limited by the types of filters that can be used.
Local vacuum/local filter systems were developed next. These generally comprise a portable housing, having a filter and local vacuum, and a length of flexible tubing connected at one end to the filter inlet and its other end adapted to be located adjacent the smoke plume. The local vacuum sequentially draws the smoke plume through the flexible tubing and the filter. Local vacuum/local filter systems have many positive features including a comparable low cost, portability for use between rooms on an as-needed basis, ease of filter replacement, flexibility to use various filters having desired characteristics, and restriction of contamination to the disposable flexible tubing, and the disposable filter. However, local vacuum/local filter systems have not been the final answer as they also have significant drawbacks. Most local vacuum/local filter systems use local vacuums which generate significant noise. Most local vacuum/local filter systems occupy valuable floor space, and associated power cords and tubing may drape onto the floor creating a hazard. Finally, local vacuum/local filter systems generally recirculate the filtered air back into the treatment room.
Recently, centralized vacuum/centralized filter systems have been developed in an attempt to address the problems presented by local vacuum/local filter systems. An example of a centralized vacuum/centralized filter system is described in U.S. Pat. Nos. 5,264,026 and 5,409,551, both to Paul and both entitled CENTRALIZED LASER PLUME EVACUATION SYSTEM THROUGH ARTICULATING ARMS. The centralized vacuum/centralized filter systems are best described as a modification to the known centralized vacuum/local filter systems. The centralized vacuum/centralized filter system generally comprises a central vacuum, usually located in the basement of a health care facility, a central filter downstream from the central vacuum, a centrifugal separation tank upstream from the central vacuum, and duct work extending throughout the health care facility connecting to the centrifugal separation tank. It is known to connect the duct work of the centralized vacuum/centralized filter system to tubing running within an articulating arm mounted within a treatment room, the tubing ending at an outlet on the arm control panel. A disposable flexible tube is connected at one end to the outlet on the arm control panel with its other end adapted to be located adjacent the smoke plume. The central vacuum draws a smoke plume sequentially through the disposable tubing, the arm tubing, the duct work, and the centrifugal separation tank. The central vacuum then exhausts the smoke plume through the central filter where contaminants are removed.
The centralized vacuum/centralized filter system as described occupies no floor space, eliminates associated cords and tubing from the floor and reduces noise in the operating room by placing the central vacuum at a distant location. However, centralized vacuum/centralized filter systems have significant draw-backs. Centralized vacuum/centralized filter systems are expensive both to install and to operate on a per procedure basis. Extensive duct work and tubing must be run throughout the health care facility, and a large, high powered central vacuum must be used to provide the necessary suction. In addition, repair can be difficult as the majority of the duct work is normally in service areas above ceiling or within floors. Furthermore, the central filter does not allow selective use of filters having desired characteristics for certain procedures. A significant amount of energy must be used to maintain the vacuum throughout the extensive duct work. Most importantly, as the central filter is placed after the central vacuum, all interior surfaces of the arm tubing, duct work, centrifugal separation tank and vacuum unit are exposed to the contaminated smoke plume. The '026 and '511 patents suggest frequent introduction of a liquid disinfectant/antimicrobial solution into the arm tubing and duct work to address this concern. However, it is questionable whether this procedure would be effective absent the complete flushing of the arm tubing and duct work, especially at bends and incongruities of the arm tubing and duct work where particulate is most likely to collect. Finally, the centralized vacuum/centralized filter system are inappropriate to install in smaller facilities such as individual physician's offices, surgi centers, clinics and ambulatory centers.
Accordingly, it would be useful to have a filter system for a contaminated fluid stream that does occupy floor space, does not drape power cords and tubing on the floor, is quiet but provides a powerful vacuum, allows for the easy replacement of filters, is inexpensive to install and use, and where only disposable portions of the system come in contact with the smoke plume when contaminated.